Processing apparatus of processing wafer sheets

ABSTRACT

A processing apparatus of the invention includes a rotary processing part for rotating and drying plural sheets of objects to be processed collectively in order to allow the object to be rotated immediately after they are accommodated in the rotary processing part and a balance adjusting mechanism for adjusting balance of the rotary processing part by moving counterweights in accordance with the number of the objects. Further the processing apparatus further includes a counter for counting the number of the objects accommodated in the rotary processing part and a control unit for controlling the balance adjusting operation of the balance adjusting mechanism in accordance with a predetermined relationship between the number of objects and the respective positions of the counterweights.

BACKGROUND OF THE INVENTION

The present invention relates to a processing apparatus for and aprocessing method of executing a treatment including a process in whichan object to be processed, such as a semiconductor wafer, is rotated soas to scatter liquid sticking on a surface of the object by centrifugalforce due to its rotation.

For example, in the manufacturing process for a semiconductor device,various cleaning systems are employed for removing contamination, suchas particles and organic contaminants, on the surface of thesemiconductor wafer. Note, the semiconductor wafer will be referred as"the wafer", hereinafter. Above all, a cleaning system of the wet typewhere the wafer can be cleaned by dipping it into cleaning liquid in aprocessor has merit to remove the particles on the wafer effectively.

In order to permit a continuous batch process, the wet type cleaningsystem comprises a loader for loading, for example, twenty five wafersinto the processing apparatus with every carrier, transporting means fortransporting fifty wafers corresponding to two carriers loaded by theloader collectively, a processing unit arranged for cleaning and dryingthe wafers, which have been transported by the transporting means, inbatch processing, and an unloader for unloading the wafers cleaned anddried. With these elements, this cleaning system is called "a wetstation" in widespread use.

At respective processing sections constituting the wet station, avariety of chemical treatments, such as ammonia treatment, hydrogenfluoride treatment, sulfuric acid treatment, hydrochloric acid treatmentetc., and a washing treatment with pure water are carried out by turns.

Further, a drying treatment is executed finally.

As the processing section for drying the wafers, there are well-known arotary processing part in which the wafers are dried by shakingtreatment-liquid off wafer surfaces due to the action of centrifugalforce caused by rotating the wafers, and a IPA processing part in whichthe wafers are dried by draining while supplying water-amiable IPAisopropyl alcohol:(CH₃)₂ CHOH! steam to the wafer surfaces,conventionally. The rotary processing part which is also called "spindryer" has the advantage of simple structure and low running costsbecause of disuse of an explosion-proof mechanism, in comparison withthose of the IPA processing part. In the prior art, a spin dryerdisclosed in e.g. Japanese Utility Model Publication (kokai) No. 5-83870is well-known as the rotary processing (drying) part.

We now describe a structure of the conventional rotary drying part inbrief. As shown in FIG. 1, a processing chamber 200 arranged in therotary processing part includes a pair of rotating shafts 201, 202arranged in series. The rotating shaft 201 is one to which rotatingforce of a motor 203 is transmitted, while the other shaft 202 is adriven shaft. To the rotating shafts 201, 202, rotors 205, 206 inprocessing chamber 200 are attached respectively. A plurality of wafersW are collectively carried in their juxtaposed condition by constraintmechanisms 207, 208 bridging between the rotor 205 and the rotor 206. Asshown in FIG. 2, the constraint mechanisms 207, 208 are provided, onsurfaces thereof abutting on the wafers W, with numerous grooves 210which are formed at constant intervals. In use, by inserting theperipheries of the wafers W into the groove 210, it is possible to carrythe plural wafers W between the constraint mechanisms 207, 208 whilekeeping the wafers W to be juxtaposed apart from each other at regularintervals.

Further, against the processing chamber 200, not-shown intake port andexhaust port are connected for flowing air in the chamber 200. Since thewafers W are rotated while ventilating the chamber 200 through theintake and exhaust ports, it is possible to scatter moisture sticking onthe wafers W by centrifugal force and also to dry the wafers W per se bythe flowing of fresh air.

In such a rotary processing part, however, there is a case that thecenter of gravity of the wafers W and the center of rotation (of therotating shafts 201, 202) do not overlap with each other. If the wafersW are rotated while leaving such a condition, vibrations may be causedduring its rotation because of the ill-balanced rotary processing part.Therefore, from the points of view of the prevention of noise and theimprovement in durability of the apparatus, it is necessary to adjustthe balance of the rotary processing part so as not to increasevibrations caused by the rotation of the wafers W, thereby suppressingcentrifugal whirling of the shafts. For this purpose, in the aboveprocessing part, two autobalancers 211, 212 are mounted on the rotatingshafts 201, 202 rotating together with the wafers W respectively, fortheir integral rotation. In detail, the adjustment of balance isexecuted by moving counterweights accommodated in the autobalancers 211,212 to appropriate positions.

It should be noted that the autobalancers 211, 212 have similarstructures to each other. Therefore, we now describe the structure ofautobalancer 211 mounted on the shaft 201 representatively. As shown inFIGS. 3A and 3B, the autobalancer 211 is provided with a pair of insidecounterweights 213, 214. Since the counterweights 213, 214 rotatetogether with the shaft 201, centrifugal forces 215, 216 are applied onthe counterweights 213, 214, respectively. In arrangement, thecounterweights 213, 214 can be angularly moved freely within 360degrees. In this regard, FIG. 3A shows a condition that thecounterweight 213 is diametrically opposite to the counterweight 214 (at180 degrees). In this case, a direction of centrifugal force 215 appliedon the counterweight 213 is opposite to that of centrifugal force 216applied on the counterweight 214, a resultant force of the centrifugalforces 215, 216 amounts to zero by their mutual negation.

While, FIG. 3B shows a condition that the counterweights 213, 214 areangularly moved from the positions of FIG. 3A by predetermined angles.In this case, the autobalancer 211 during rotation is subjected to aresultant force 217 consisting of the centrifugal force 215 applied onthe counterweight 213 and the centrifugal force 216 applied on thecounterweight 214. In this way, by optionally changing the positions ofthe counterweights 213, 214 in the autobalancers 211, 212, it ispossible to change both direction and magnitude of the resultant force217 consisting of the centrifugal force 215 applied on the counterweight213 and the centrifugal force 216 applied on the counterweight 214.Thus, with the optional establishment in direction and magnitude of theresultant force 217, the balance of the wafers W rotating in theprocessing chamber 200 is adjusted in the conventional processing part.Note, as mentioned above, the autobalancer 212 has a structure similarto that of the autobalancer 211.

Now, as a method of seeking the most suitable positions of thecounterweights 213, 214 in the autobalancer 211, 212 for adjusting thebalance, the following method has been generally adopted conventionally.That is, in order to examine a relationship between the positions of thecounterweights 213, 214 and vibratory values, it is executed at leastonce to rotate the wafers W and measure their vibrations whilesuccessively changing the positions of counterweights 213, 214 by e.g.five degrees (5°) at a time on condition that the wafers W areaccommodated in the processing chamber 200 of the rotary processing partpreviously. In this way, the most suitable positions of thecounterweights 213, 214 to reduce the vibrations the most are determinedon the basis of the obtained relationship.

However, it is impossible to seek the most suitable positions of thecounterweights 213, 214 unless accommodating the wafers W in theprocessing chamber 200 and rotating them practically. Consequently, atleast one superfluous rotating operation must be carried out beforestarting the rotation of the wafers W for dry, which is far from theshortening of processing period. Furthermore, according to the method,since the rotating operation of the wafers W has to be carried outdespite that the balance is not adjusted yet, there is a problem thatremarkable vibrations are produced during the rotating operation.

Recently, it has been found that the number of wafers W accommodated inthe processing chamber 200 of the rotary processing part is closelyrelated with the respective positions of the counterweights 213, 214.That is, to take an instance of the rotary processing part which is soconstructed as to rotate the processing chamber 200 allowing e.g. amaximum of fifty sheets of wafers W to be accommodated collectively,there is a fact that when fifty wafers W are accommodated in the chamber200, an operator has only to move the counterweights 213, 214 toprescribed angular positions. Similarly, the operator has only to movethe counterweights 213, 214 to another prescribed angular positions incase of forty nine wafers W, while the operator has only to move thecounterweights 213, 214 to the other prescribed angular positions incase of forty eight wafers W. That is, it has been found that, if thenumber of wafers W can be found out, the most suitable positions of thecounterweights 213, 214 allowing their movement to be reduced to themaximum can be determined automatically. In this way, if only examiningthe relationship between the number of the wafers W and the positions ofthe counterweights 213, 214 previously, the operator has only to countthe number of wafers W and sequent adjust the positions of thecounterweights 213, 214 in accordance with such preset data,practically. Therefore, in such a case, there is no need for theoperator to repeat the superfluous rotating operations every process.

Under such a circumstance, in the spin dryer disclosed in the abovepublication No. 5-83870, a counter consisting of a pair of light emitterand light receiver is provided in the rotary processing part forcounting the number of wafers W accommodated therein and the adjustmentfor balance is carried out on the basis of the obtained discrete value.According to the method, the operator does not have to carry out thesuperfluous rotating operation before rotating the wafers for drying.

However, since the above spin dryer is adapted so as to begin to countthe wafers for the balance adjustment after they have been accommodatedin the rotary processing part, it is impossible to start to rotate thewafers as soon as they have been accommodated in the rotary processingpart. For example, in the above-mentioned "wet" type of cleaning system,the wet wafers on which water is sticking due to the previous cleaningand sequent rinsing steps are to be accommodated in the rotaryprocessing part. Accordingly, if such wet wafers are left as they arefor a long time, the water will evaporate naturally, so that so-called"water marks" will appear on the surfaces of the wafersdisadvantageously.

In addition, since the spin dryer in the above publication No. 5-83870has the counter arranged in the rotary processing part, the waterscattering by the rotation of the wafers may stick on the light emitterand the light receiver to cause their malfunctions. Furthermore, sinceit takes a long time from the dryer's accommodating the wafers in therotary processing part till the starting, it is difficult to shorten theprocessing period. Additionally, since the rotary processing part of thespin dryer is not so wide in general, there are some cases of difficultyto arrange the counter in the rotary processing part.

SUMMARY OF THE INVENTION

Accordingly, it are therefore an object of the present invention toprovide means which is capable of starting to rotate objects to beprocessed as soon as they have been accommodated in a rotary processingpart.

The object of the present invention described above can be accomplishedby a processing apparatus comprising:

a rotary processing part for rotating and drying plural sheets ofobjects to be processed collectively;

a balance adjusting mechanism having a counterweight, for adjusting thebalance of the rotary processing part by moving the counterweights inaccordance with the number of the objects;

counting means for counting the number of the objects accommodated inthe rotary processing part; and

control means for controlling the balance adjusting operation by thebalance adjusting mechanism in accordance with a predeterminedrelationship between the number of the objects and respective positionsof the counterweights.

The object of the present invention described above can be alsoaccomplished by a processing apparatus:

one or more processing parts for processing plural sheets of objects tobe processed;

a rotary processing part for collectively rotating and drying theobjects processed by the processing parts;

a balance adjusting mechanism having a counterweights, for adjusting thebalance of the rotary processing part by moving the counterweights inaccordance with the number of the objects;

counting means for counting the number of the objects before the objectsare processed by the processing parts; and

control means for controlling the balance adjusting operation by thebalance adjusting mechanism in accordance with a predeterminedrelationship between the number of the objects and respective positionsof the counterweights.

In the above-mentioned processing apparatuses, preferably, the controlmeans controls the balance adjusting mechanism in a manner that thebalance adjusting operation of the balance adjusting mechanism has beenfinished until the objects are accommodated in the rotary processingpart at the latest.

Providing that a period from a beginning of the balance adjustingoperation to the end is represented by a letter A while a period from abeginning of transferring said object from a former processing part justbefore said rotary processing part to said rotary processing part to theend of transferring after which said objects are able to berotary-processed is represented by a letter B,

more preferably the control means is constructed so that, in case ofA≦B, the transferring of the objects into the rotary processing part isstarted as soon as the balance adjusting operation has been started,while in case of A>B, the objects wait for at least a time A-B since thebalance adjusting operation was started, at the former processing partjust before said rotary processing part, then the transferring of theobjects into the rotary processing part is started.

Alternatively, it is also preferable that the predetermined relationshipbetween the number of the objects and the position of the counterweightis introduced from a predetermined relationship between the number ofthe objects and resultant force of the counterweights and wherein,providing that the number of the objects is represented by a variable xwhile the resultant force is represented by a variable y, certainconstant values are represented by constants a and b the predeterminedrelationship between the number of the objects and the resultant forceis expressed by an equation as below.

    y=a x+b

According to the invention there is also provided a method of processingplural sheets of objects to be processed, on condition of making use ofa processing apparatus comprising a rotary processing part for rotatingand drying the objects collectively and a balance adjusting mechanismhaving a plurality of counterweights for balancing the rotary processingpart, the method comprising steps of:

adjusting balance of the rotary processing part by moving thecounterweights in accordance with the number of the objects accommodatedin the rotary processing part; and thereafter,

rotating the object collectively in order to process them;

wherein the balance adjusting step has been finished at the latest untilthe objects are accommodated in the rotary processing part and are ableto be rotary-processed; and

the rotating step is started as soon as the objects have beenaccommodated in the rotary processing part.

In the present method, preferably, the balance adjusting step is carriedout after the drying of the objects at the rotary processing part hasbeen finished in the previous routine and before the objects areaccommodated in the rotary processing part and are able to berotary-processed in the present routine.

Alternatively, providing that a period from a beginning of the balanceadjusting operation to the end is represented by a letter A while aperiod from a beginning of transferring said object from a formerprocessing part just before said rotary processing part to said rotaryprocessing part to the end of transferring after which said objects areable to be rotary-processed is represented by a letter B, morepreferably case of A≦B, to transfer the objects into the rotaryprocessing part is started as soon as the balance adjusting step hasbeen started, while in case of A>B, the objects wait for at least a timeA-B since the balance adjusting operation was started, at the formerprocessing part just before said rotary processing part, then totransfer the objects into the rotary processing part is started.

Alternatively, it is also preferable that the balance adjusting step tomove the counterweights in accordance with the number of the objectsaccommodated in the rotary processing part is carried out in accordancewith a predetermined relationship between the number of the objects andresultant force of the counterweights and wherein, providing that thenumber of the objects is represented by a variable x while the resultantforce is represented by a variable y, certain constant values arerepresented by constants a and b the predetermined relationship betweenthe number of the objects and the resultant force is expressed by anequation as below.

    y=a x+b

More preferably, the predetermined relationship between the number ofthe objects and the resultant force is obtained by executing both of therotating step for rotating the objects accommodated in the rotaryprocessing part and the balance adjusting step for balancing the rotaryprocessing part, with respect to a variety of different numbers of theobjects.

More preferably, the different numbers of the objects contain all thenumbers of the objects.

Alternatively, the different numbers of the objects contain numbers ofthe objects picked up at intervals of a definite number of the objects.

In the present method, preferably, the number of the objects is countedbefore a process carried out previous to the rotating step.

The above and other features and advantages of this invention willbecome apparent, and the invention itself will best be understood, froma study of the following description and appended claims, with referencehad to the attached drawings showing a preferred embodiment of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an inside structural view of a rotary processor of aconventional processing apparatus;

FIG. 2 is an enlarged cross sectional view showing a condition thatmargins of the wafers are inserted into grooves of a retainer lever;

FIGS. 3A and 3B are explanatory views of an adjusting operation carriedout by an auto balancing machine;

FIG. 4 is a perspective view of a cleaning system in accordance with thepresent invention;

FIG. 5 is a perspective view of an unloader of the cleaning system;

FIG. 6 is an enlarged cross sectional view taken along a line VI--VI ofFIG. 5;

FIG. 7 is an explanatory view of an inside structure of a rotaryprocessor in accordance with the embodiment of the present invention;

FIG. 8 is an explanatory front view of the inside structure of therotary processor in accordance with the embodiment of the presentinvention;

FIG. 9 is an enlarged front view of the wafer constrained by a lowerconstraining mechanism and an upper constraining mechanism;

FIG. 10 is a plan view of a processing chamber;

FIG. 11 is a block diagram showing control of the cleaning system;

FIG. 12 is a graph showing a relationship between the number x of wafersand the resultant force y of counterweights; and

FIG. 13 is a flow chart showing steps of adjusting balance in accordancewith the embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings, preferred embodiments of the presentinvention will be described on the basis of a cleaning system 1 forcleaning wafers W as one example of the objects to be processed.

FIG. 4 is a perspective view of the cleaning system 1.

Being classified roughly, the cleaning system 1 comprises aloading/pickup section 2 for picking up the wafers W before cleaning,which have been brought in blocks of a carrier C, from the carrier C intheir oriented manner, a cleaning/drying section 3 for cleaning andsequent drying the plural wafers W (e.g. two carriers, i.e. fiftysheets) picked up by the loading/pickup section 2, in a so-called"batch" manner collectively and a charging/unloading section 4 forcharging the wafers W cleaned and dried in the section 3 into thecarriers C in every predetermined number of wafer W (e.g. twenty-fivesheets) and unloading the wafers W in blocks of the carrier C.

The loading/pickup section 2 includes a loading part 5 for loading andmounting the carrier C which is capable of accommodating the wafers Wbefore cleaning (e.g. twenty-five sheets), a pick-up part 6 arrangedadjacent to the part 5 for picking up the wafers W from the carrier Cand positioning them in a low, and a transporting unit 7 fortransporting a predetermined number of carriers C (e.g. two carriers)from the loading part 5 to the pick-up part 6 at a time.

According to the embodiment, in the cleaning/drying section 3, thefollowing parts are arranged in order from the side of theloading/pickup section 2 to the side of the charging/unloading section4: a processing part 11 for cleaning and drying a wafer chuck 36 of aconveying unit 30 described later, a processing part 12 for cleaning thewafer W by washing liquid, processing parts 13 and 14 for rinsing thewafer W cleaned at the part 12, a processing part 15 for cleaning thewafer W by washing liquid, processing parts 16 and 17 for rinsing thewafer W cleaned at the part 15, a processing part 18 for cleaning anddrying a wafer chuck 38 of a conveying unit 32 also described later, anda rotary processing part 19 for rotating the wafer W cleaned at theparts 11 to 17 while circulating clean air thereby to scatter watersticking to the surface of the water W by centrifugal force and dry thewafer W by the clean air.

At the processing parts 11 and 18, the wafer chucks 38, 38 are cleanedby using pure water (example) and thereafter, they are dried. Further,at the processing parts 12 and 15, the wafer W is cleaned by differentkinds of washing liquids from each other, generally. As an example, inthe processing part 12, so-called "SC1" cleaning process using alkalinewashing liquid, such as ammonium hydrogen peroxide (NH₄ OH/H₂ O₂ /H₂ O),is carried out to remove impurities on the surface of the wafer W, suchas organic contaminants, particles or the like. While, in the processingpart 15, so-called acid "SC2" cleaning process using e.g. hydrochloricacid and hydrogen peroxide (HCl+H₂ O₂) is executed to remove metal ionsand stabilize the surface of the wafer W. Further, in the processingparts 13 and 14, and the processing part 16 and 17, the rinsing of thewafer W is carried out by using washing liquid such as pure water. Inthe processing part 19, the wafer W is rotated in order to scatter thewashing liquid sticking on the surface due to the centrifugal force andthereafter, the wafer W is subjected to the drying process where cleanair circulates for removing water marks on the surface.

Note, the arrangement and combination of the respective processing parts11 to 19 may be optionally modified in accordance with the sorts ofcleaning of the wafer W. As the case may be, a certain processing partmay be eliminated or conversely, another processing part may be added inthe modification. For example, a processing part using sulferic acid andhydrogen peroxide (H₂ SO₄ +H₂ O₂) may be incorporated. Note, it isgeneral that the rotary processing part 19 for drying the wafer W isarranged at the latest.

The charging/unloading section 4 is provided with a charging part 20having a constitution similar to that of the pick-up part 6 of theloading/pickup section 2, an unloading part 21 having a similarconstitution similar to that of the loading part 5, and a not-showntransporting unit similar to the transporting unit 7.

The cleaning/drying section 3 is provided, on a front side thereof (i.e.the front side of FIG. 4), with three conveying unit 30, 31, 32 whichare successively arranged from the side of the loading/pickup section 2to the side of the charging/unloading section 4. The conveying units 30,31, 32 are adapted so as to be slidable along a guide 33 in thelongitudinal direction of the cleaning system 1. The respectiveconveying units 30, 31, 32 include wafer chucks 36, 37, 38,respectively. Owing to the wafer chucks 36, 37, 38, each of theconveying units 30, 31, 32 is capable of holding the prescribed numberof wafers W (e.g. fifty wafers W corresponding to two carriers C)collectively. In these conveying units, since the unit 30 on the side ofthe loading/pickup section 2 slides along the guide 33 while retainingthe prescribed number of wafers W by the wafer chuck 36, the wafers Wpicked up from the pick-up part 6 are collectively transported to theprocessing parts 12, 13, 14 in the cleaning/drying section 3, in order.Further, by the sliding movement of the center conveying unit 31 alongthe guide 33 while retaining the prescribed number of wafers W by meansof the wafer chuck 37, the wafers W are collectively transported to theprocessing parts 14, 15, 16, 17 in the cleaning/drying section 3, inorder. Since the unit 32 on the side of the charging/unloading section 4slides along the guide 33 while retaining the prescribed number ofwafers W by the wafer chuck 38, the processing unit 32 collectivelytransports the wafers W from the processing part 17 to the rotaryprocessing part 19 and sequentially, from the part 19 to the unloadingpart 20 of the charging/unloading section 4.

Hereat, referring to FIGS. 5 and 6, we now describe details of thepick-up part 6 constituting the loading/pickup section 2.

The pick-up part 6 is provided, on an upper surface thereof, with amovable stage 41 which drops (i.e. to move a direction of a dotted arrowof FIG. 6) by the shrinking operation of a cylinder 40. The movablestage 41 has openings 44, 45 formed to allow wafer carriages 42, 43through. About each margin of the openings 44, 45, a guide member 46 anda pusher 47 are arranged to face each other, interposing each of theopenings 44, 45 therebetween. Two carriers C, which have beentransported from the above-mentioned loading part 5 to the pick-up part6 by the transporting unit 6, are positioned by the guide members 46 andthe pushers 47 and then fixed in prescribed positions on the movablestage 41, where not-shown openings formed in respective lower surfacesof the carriers C coincide with the openings 44, 45, respectively.

The wafer carriages 42, 43 are respectively provided, on upper surfacesthereof, with retainer grooves 50 (e.g. twenty five grooves) which areformed at predetermined intervals for receiving and retaining lowermargins of the wafers W, respectively. Being fixed on respective upperends of struts 51, the wafer carriages 42, 43 are arranged so as toalways maintain on a same level with each other. Note, the strut 51fixing the wafer carriage 42 on the front side is constructed so as tomove close to the other carriage 43.

A wafer counter 55 is arranged above the pick-up part 6. The wafercounter 55 comprises a L-shaped guide member 56 which is movable alonglaterals of the wafer carriages 42, 43 and a curved member 57 carried byan upper end of the guide member 56. Arranged on an under surface of thecurved member 57 are a pair of light emitter 61 and light receiver 62both of which oppose level with each other and another pair of lightemitter 63 and light receiver 64 both of which also oppose level witheach other. The light emitter 63 and the light receiver 64 are arrangedsomewhat higher than the light emitter 61 and the light receiver 62,respectively.

The guide member 56 of the wafer counter 55 is normally arranged so asto retreat to the frontmost position of the pick-up part 6. As will bedescribed later, when the wafers W are pushed up relative to the carrierC by the wafer carriages 42, 43, the guide member 56 moves along thelaterals of the wafer carriages 42, 43. With this movement of the guidemember 56, the light emitter 61 and the light receiver 62 opposing onthe lower side of the curved member 57 are arranged so as to interposethe upper ends formed on the peripheries of the wafers W therebetween,as shown in FIG. 6. Consequently, when the light emitter 61 and thelight receiver 62 pass through the respective upper end of the specifiedwafer W, the light emitted from the light emitter 61 is interrupted bythe upper end of the wafer W, so that the light receiver 62 cannotreceive the light. Owing to this event, the processing apparatus of theinvention is capable of detecting the presence of the wafers W to countthem. After counting the wafers W, the strut 51 fixing the front wafercarriage 42 is moved so that it approaches the innermost wafer carriage43. Thus, the wafers W are gathered to one side in a row.

Note, as mentioned above, the light emitter 63 and the light receiver 64opposing on the upper side of the curved member 57 are arranged somewhathigher than the light emitter 61 and the light receiver 62. In addition,the positions of the light emitter 63 and the light receiver 64 areestablished in such a manner that the light emitted from the lightemitter 63 can pass somewhat above the upper ends of the wafers W andfinally enter into the light receiver 64. Therefore, if the wafers Wpushed up relative to the carriers C by the wafer carriages 42, 43 arenot arranged in a row, for example, if a certain wafer W is not acceptedin the retaining groove 50 of the wafer carriage 42, 43 to projectupward, namely, in the "jumping slot" condition, the light from thelight emitter 63 would be interrupted by the projecting wafer W, so thatthe light receiver 64 cannot receive the light. In this way, it ispossible to detect whether the wafers W are arranged in a low or not andalso detect a deviation of angle of the orientation flat.

Next, referring to FIGS. 7 to 10, we describe the constitution of therotary processing part 19 installed in the cleaning/drying processingsection 3 of the cleaning system 1 in detail.

As shown in FIG. 7, arranged in the rotary processing part 19 is a frame70 on which a processing chamber 71 to rotating the wafers W forprocession is supported. A pair of rotary shafts 72, 73 are arranged onboth side surfaces of the processing chamber 71. The rotary shaft 72corresponds to a driven spindle, while the rotary shaft 74 correspondsto a drive spindle rotated by a motor 74.

According to the embodiment, the rotary shafts 72, 73 are provided withautomatic balancing devices (alias autobalancers) 75, 76, respectively.These autobalancers 75, 76 rotate together with the rotary shafts 72, 73integrally. Similar to those in FIGS. 3A and 3B, each of theautobalancers 75, 76 includes two counterweights built-in for balancingthe wafers W. In operation, by moving the counterweights, it is possibleto balance the whole wafers W collectively accommodated in theprocessing chamber 71 of the rotary processing part 19.

The processing chamber 71 is formed to have an opening 80 on the upperside. A lid body 81 for closing the opening 80 is carried by an axle 83penetrating a bracket 82 standing on the side surface of the processingchamber 71. When lifting up to rotate the lid body 81 about the axle 83as a pivot, the upper part of the processing chamber 71 is opened. Thelid body 81 shown with a solid line of FIG. 7 is in the lifted conditionto open the upper side of the chamber 71. On the contrary, by loweringthe lid body 81 about the axle 83, the chamber 71 can be closed. In FIG.7, the lid body 81' shown with a two-dot chain line exhibits thecondition to close up the chamber 71. On the side surface of the lidbody 81, ionizers 85, 85 are attached for removing electric charge inthe air supplied into the chamber 71, which will be described later.

Transferred above the processing chamber 71 are the wafers W (e.g. fiftywafers) which are held by the wafer chuck 38 of the above-mentionedconveying unit 32. The wafers W above the chamber 71 in this way areones which has been already subjected to the prescribed processes in theprocessing parts 12 to 17.

This conveying unit 32 includes a driving part 90 for driving the waferchuck 30. Above a traveling part 91 which travels in the longitudinaldirection of the cleaning system 1, the driving part 90 is supported byan elevating part 92. In FIG. 7, the driving part 90 shown with a solidline designates the condition that it has been lifted up due to therising of the elevating part 92. While, the driving part 90' shown witha two-dot chain line exhibits the condition that it has been lowered bythe descent of the elevating part 92. The wafer chuck 38 has a pair ofright and left grip members 93, 93 projecting from the driving part 90.Each grip member 93 is provided with two arms 94, 94 which are hungtherefrom and between which upper and lower grip rods 95, 95 areattached to bridge a gap therebetween.

FIG. 9 shows a front view of the wafer chuck 38. Owing to the rotationof the grip members 93, 93, the left and right arms 94, 94 can pivot inthe directions of arrows 96, 96. The arms 94, 94 are adapted in a mannerthat when pivoted to approach each other, the arms 94, 94 can grasp thewafers (e.g. fifty wafers) W between the grip rods 95, 95 collectively.Each wafer W is shaped to have a substantially circular periphery andprovided, at a part thereof, with an orientation flat part W'. In thecleaning system 1 of the embodiment, the wafers W are collectivelygrasped between the grip rods 95, 95 while the respective orientationflat parts W' point to the upward.

Further, the grip rods 95, 95 are provided, on respective insidesthereof, with a plurality of grooves (e.g. fifty grooves) 97 whichcorrespond to the wafers W, respectively, and which are formed at evenintervals for retaining the peripheries of the wafers W. Therefore, whenthe arms 94, 94 of the wafer chuck 38 are pivoted to approach eachother, the conveying unit 32 is capable of grasping the wafers Wjuxtaposed at even intervals collectively while, for example, fiftywafers W are inserted into the grooves 97 on the grip rods 95, 95. Theconveying unit 32 is so constructed that, for example, fifty wafers Wgrasped between the grip members 95, 95 can be moved above theprocessing chamber 71, as shown in FIG. 7. Further, the descendingoperation of the elevating part 92 allows the wafers W, which aregrasped by the grip members 95, 95 in a row, to descend whilemaintaining their postures directing their orientation flats W' to theupward, whereby the wafers W can be loaded into the processing chamber71 through the opening 80.

As shown in FIG. 7, in the processing chamber 71, rotors 100, 101 areattached to the leading ends of the rotary shafts 72, 73. Between therotor 100 and the rotor 101, a lower constraint mechanism 102 and anupper constraint mechanism 103 are installed in the chamber 71. Sincethe rotors 100, 101 are connected with each other through theintermediary of the constraint mechanisms 102, 103, the rotatingoperation of the motor 74 allows the rotors 100, 101 to be rotatedtogether with the rotary shafts 72, 73 integrally.

As shown in FIG. 9, the lower constraint mechanism 102 comprises threepieces of double rod bodies 106, 107, 108 each of which can be obtainedby press-fitting, for example, a stainless pipe into a Teflon(trademark) pipe and which are secured on the rotors 100, 101,respectively. The rod bodies 106, 107, 108 are provided, on theirsurfaces abutting on the wafers W (i.e. upper surfaces in the figure),with respective grooves 110, 111, 112 which correspond to the grooves 97formed on the inside of the grip members 95 95. As mentioned above, whenthe wafers W (e.g. fifty wafers) grasped between the grip members 95, 95of the wafer chuck 38 are loaded in the processing chamber 71 due to thedescent movement of the elevating part 92 of the conveying unit 32, theperipheries of the wafers W are inserted into the grooves 110, 11, 112.Under such a condition, the grooves 110, 112 of the pipe bodies 106, 108serve to bear up the wafers' own weights, while the grooves 111 of therod body 107 serve to prevent the wafers W from tilting. Consequently,the wafers W can be held so as to stand in a line at regular intervalswhile keeping their postures to stand upright on the rod bodies 106,107, 108.

Similarly, the upper constraint mechanism 103 includes three pieces ofdouble rod bodies 115, 116, 117 which can be obtained by press-fitting,for example, stainless pipes into Teflon (trademark) pipes,respectively, as shown in FIG. 9. Note, the rod bodies 115, 117 on bothsides are formed to be circular rods with no grooves. The rod body 116is provided, on the surface abutting on the wafers W (i.e. lower surfacein the figure), with grooves 118 which respectively correspond to thegrooves 110, 111, 112 formed on the lower rod bodies 106, 107, 108 ofthe aforementioned lower constraint mechanism 102. Having two slantedsurfaces 118a, 118b, the groove 110 is formed to have a substantiallyV-shaped configuration.

As shown in FIG. 10, the constraint mechanism 103 includes a T-shapedbracket 120 which is arranged on the side of respective base ends of therod bodies 115, 116, 117 and a T-shaped bracket 130 which is arranged onthe side of respective leading ends of the rod bodies 115, 116, 117. Thebracket 120 on the side of the base ends is attached to a shaft 119rotatably supported by the rotor 101. Therefore, by rotating the wholeconstraint mechanism 103 on the upper side about the shaft 119, it ispossible to selectively realize a state where the mechanism 103 isrotated by an angle of 90 degrees to escape upward of the processingchamber 71 as shown with a solid line of FIG. 7 and another state wherethe mechanism 103 is inclined horizontally thereby to hold the wafers Waccommodated in the processing chamber 71, between the mechanism 103 andthe lower constraint mechanism 102 as shown with a chain line 103' ofFIG. 7.

As will be described later, under condition that, for example, fiftywafers W collectively delivered from the wafer chuck 38 are held by theupper and lower constraint mechanisms 102, 103, the peripheries of thewafers W are inserted into the grooves 110, 111, 112 of the rod bodies106, 107, 108 of the lower constraint mechanism 102 and the grooves 118of the rod body 106 of the upper constraint mechanism 103, so that thewafers W are held in parallel at even intervals. Further, the rotationof the wafers W, which are restrained by the lower and upper constraintmechanisms 102, 103, with respect to rotors 100, 101 are prevented dueto the abutment of the orientation flats W' with either of the slantedsurfaces 118a, 118b.

As shown in FIG. 10, the shaft 119 rotatably carried by the rotor 101 isprovided, on one end thereof, with a meshing part 121. Mounted on thewall of the processing chamber 71 is a bearing unit 124 which carries ashaft 123 so as to rotate and reciprocate thereon. The shaft 123 isprovided with a meshing part 122 which can mesh with the meshing part121 of the shaft 119. At the exterior of the processing chamber 71, theshaft 123 has a timing pulley 125 attached thereto. Through the timingpulley 125, rotationally driving force of not-shown motor is transmittedto the shaft 123. The rear end of the shaft 123 is connected with apiston rod 127 of a cylinder 126 fixed on the exterior of the processingchamber 71 through a member 128. With the arrangement, the shaft 123 cango ahead and back in accordance with expansion and contraction of thepiston rod 127 due to the operation of the cylinder 126.

While, the bracket 130 on the side of the leading end can maintain itslocked condition that it is fixed by a switching pin 131 attached to therotor 100 and the unlocked condition that it is not fixed. On the wallof the chamber 71, a pusher 132 for bringing the switching pin 131 intothe locked condition and another pusher 133 for bringing the switchingpin 131 into the unlocked condition are arranged to oppose to each otherin series with the pin 131.

Further, the processing chamber 71 is provided, on the opposite walls,with windows 135, 136 which allow the light through. The chamber 71further includes a floodlight 137 attached on the wall to emit the lightinto the interior of the processing chamber 71 and a light-receivingsensor 138 also attached to the wall for receiving the emitted light.When the wafers W are accommodated in the processing chamber 71, thelight is interrupted by the wafers W, so that the light-receiving sensor138 cannot detect the light. Thus, owing to this phenomenon, it ispossible to detect the presence of the wafers W.

In FIG. 7, arranged beneath the processing chamber 71 is a gas-liquidremoving mechanism 140 which is constructed in the frame 70. Thegas-liquid removing mechanism 140 is provided in order to suck theinterior of the chamber 71 and remove moisture or water separated fromthe wafers W in the chamber 71. The mechanism 140 consists of a drain141 and a blower 142 both of which are communicated with the processingchamber 71 through connection ducts 143, 144, respectively.

We now describe the processing of the wafers W in the above-constructedcleaning system 1.

First, by appropriate transporting means, such as a not-showntransporting robot, the carrier C is mounted on the loading part 5 inthe loading/pick-up section 2. In the state, the wafers W on the carrierC are not cleaned yet. Although the carrier C has a prescribed number(e.g. twenty five) of wafers W loaded thereon in a normal case, theremay be a case of unloading the wafers W less than the prescribed number,for some reason or other.

After aligning the orientation flats W' of the wafers W, the carriers Cmounted on the loading part 5 in the loading/pick-up section 2 aresuccessively conveyed to the adjacent pick-up part 6 by the conveyingunit 7. At each time of the operation, each carrier C is positioned bythe guide members 46 and the pusher 47. In this way, when two carriers Care positioned in a manner that the respective lower openings are rightabove the openings 44, 45 formed on the movable stage 41 respectively,it begins to descend together with the carriers C. At this time, sincethe wafer carriages 42, 43 are fixed on the upper ends of the struts 51to maintain the same levels, the wafers W loaded in the carriers C arepushed up by the wafer carriages 42, 43, so that the wafers W are pickedup from the carriers C and maintained in the grooves 50 of the carriages42, 43.

Next, the guide member 56 of the wafer counter 55 moves along the wafercarriages 42, 43 while scanning the upper ends of the wafers W betweenthe light emitter 61 and the light receiver 62 to count the number ofwafers W. Simultaneously, by the light emitter 63 and the light receiver64, it is carried out to confirm whether or not all wafers W are carriedin a row. The number of wafers W obtained in this way is then inputtedand memorized in a central control unit 150 which will be describedlater with reference to FIG. 11.

After completing to count the wafers W, the strut 51 fixed to the wafercarriage 42 on the front side of FIG. 5 is moved to approach it to thewafer carriage 43 on the interior side. Consequently, the wafers W aregathered to one side of the pick-up part 6, whereby the wafers Wcorresponding to two carriers C are arranged in a row at even intervals.In this way, the wafers W corresponds to two carriers C are brought intotheir "orderly stand-by" condition in the pick-up part 6 of theloading/pick-up section 2.

Keeping the arrangement in a row, the wafers W orderly arranged on thewafer carriages 42, 43 are then collectively grasped by the wafer chuck36 of the conveying unit 30, which has been already cleaned and dried inthe processing part 11 of the cleaning/drying processing section 3, andtransported into the processing parts 12, 13, 14 where the wafers W aredipped into the cleaning liquid for the successive cleaning process.Thereafter, the wafers W are collectively grasped by the wafer chuck 37of the conveying unit 31 and conveyed to the processing parts 15, 16, 17where the wafers W are also dipped into the cleaning liquid for thesuccessive cleaning process.

The wafers W after the prescribed cleaning processes in the processingparts 12 to 17 are then collectively grasped by the wafer chuck 38 ofthe conveying unit 32 while maintaining their orderly arrangement andconveyed to the upside of the processing chamber 71 of the rotaryprocessing part 19, as shown in FIG. 7.

In this situation, in the processing chamber 71, the lid body 81 isrotated upwardly and the opening 80 located at upper portion of theprocessing chamber 71 is opened as indicated by solid line in FIG. 7,while the constraint mechanism 103 at the upper portion is rotatedupwardly and retreated upwardly from the processing chamber 71, asindicated by solid line in the drawing.

Next, by a descent of the elevating part 92 of the conveying unit 32,the wafers W grasped by the wafer chuck 38 is introduced into theprocessing chamber 71 collectively. When the wafer chuck 38 falls up toa predetermined height, as shown in FIG. 9, the peripheries of thewafers W held between the grip members 95, 95 of the wafer chuck 38 areinserted into the grooves 110, 111, 112 formed on the rod bodies 106,107, 108 of the lower constraint mechanism 102. After mounting thewafers W on the lower constraint mechanism 102, they are released fromthe grip members 95, 95 by the opening operation of the arms 94, 94 ofthe wafer chuck 38. Thereafter, by the rising of the elevating part 92,the wafer chuck 38 is elevated to retreat upwards of the processingchamber 71. Next, the wafers W delivered to the lower constraintmechanism 102 in the above way are supported by the grooves 110, 112 ofthe rod bodies 106, 108 and prevented from tilting by the grooves 111 ofthe rod body 107. Consequently, the wafers W are maintained to stand inparallel at even intervals while keeping their upright standing on threerod bodies 106, 107, 108.

After retreating the wafer chuck 38 from the chamber 71 while mountingthem on the lower constraint mechanism 102, the upper constraintmechanism 103 is rotated downward about the shaft 119 with respect tothe rotor 101 by ninety degrees (90°). Consequently, as shown in FIG. 7,the wafers W while standing upright are collectively restricted betweenthe lower constraint mechanism 102 and the upper constraint mechanism103' shown with the dashed line. Further, by the downward rotation ofthe lid body 81 about the axle 83, the upper part of the processingchamber 71 is closed by the lid body 81' shown with the two-dot chainline of FIG. 7.

Hereat, the above-mentioned downward rotation of the lower constraintmechanism 103 is accomplished by the operation of not-shown motor. Thus,after completing to deliver the wafers W to the lower constraintmechanism 102, the shaft 123 provided on the bearing unit 124 firstlyadvances toward the interior of the processing chamber 71, so that themeshing part 122 at the end of the shaft 123 meshes with the meshingpart 121 at the end of the shaft 119 of the upper constraint mechanism103. Next, the not-shown motor is activated for rotation. The rotationof the motor is transmitted into the shaft 123 through the timing pulley125, so that the upper constraint mechanism 103 is rotated downward byninety degrees (90°). After the restriction for the wafers W between thelower constraint mechanism 102 and the upper constraint mechanism 103rotated in the above way, the pusher 132 arranged on the wall of theprocessing chamber 71 operates to urge the switching pin 131 attached tothe rotor 100. Consequently, the bracket 130 on the leading end of theupper constraint mechanism 103 is fixed by the switching pin 131 intoits locked condition. After the completion of process to restrict thewafers W between the constraint mechanisms 102, 103, the shaft 123 ofthe bearing unit 124 retreats, so that the meshing part 122 of the shaft123 and the meshing part 121 of the shaft 119 are disengaged from eachother. Correspondingly, the pusher 132 is contracted to depart from theswitching pin 131 on the rotor 100. In this way, the process foraccommodating the wafers W into the processing chamber 71 of the rotaryprocessing part 19 is completed.

While, realized in accordance with the embodiment is a condition wherethe balance adjustment of the whole wafers W collectively held betweenthe constraint mechanisms 102, 103 has been already finished by theautobalancers 75, 76 till the wafers W are accommodated in theprocessing chamber 71 at the latest.

That is, the number of wafers W counted by the wafer counter 55 at thepick-up part 6 of the loading/pick-up section 2 is inputted and storedin a central control unit 150 through a buffer 151 of FIG. 11. Then, thenumber stored in the unit 150 is inputted to a controller 152controlling the autobalancers 75, 76 through the buffer 151 again. Undersuch a situation, by moving the counterweights in the autobalancers 75,76, the balance adjustment on the basis of the number of wafers W can beexecuted.

Hereat, respective positions of the counterweights to be moved arememorized as positional data in the controller 152 previously.Accordingly, when the number of wafers W are detected by the wafercounter 55, the positions of the counterweights are selectedcorresponding to the number of wafers. Note, in order to determine thepositions of the counterweights, a relationship as shown in FIG. 12between the number x of wafers W and the resultant force y of thecounterweights is determined in advance by practically accommodatingsome numbers of wafers W in the chamber 71 to rotate them and sequentmoving the counterweights manually or automatically for the balanceadjustment. In order to determine the relationship as shown in FIG. 12,the measurement may be applied with respect to the while numbers ofwafers W (for example, all numbers containing one to fifty).Alternatively, the measurement may be executed every appropriate numbers(for example, every five sheets of wafers), while a relationship amongthe respective measurements may be complemented by an approximation (asimple equation). Since the number x (a variable) of wafers W isproportional to the resultant force y (a variable) of counterweights andtherefore, it is necessary to increase the resultant force y ofcounterweights with the increased number x of wafers W, the relationshipbetween x and y can be expressed by a simple equation as follows:

    y=ax+b

wherein "a" is an inclination of this straight line, and

"b" is the offset.

For example, as measured data, one resultant force y in case ofaccommodating five sheets of wafers W and another force y in case of tenwafers W are entered into the relationship (y=ax+b), whereby both ofcoefficients a (inclination) and b(offset) can be calculated. Then, ifsix (6) to nine (9) as the number of wafers W are entered into thevariable x in the obtained equation, it is possible to calculate thecorresponding resultant forces y, respectively.

In the embodiment, the resultant force of counterweights correspondingto the number of wafers are obtained in accordance with the relationshippredetermined in the above way and thereafter, the balance adjustment iscarried out by selecting the positions of the counterweights. Thebalance adjustment is completed till the wafers W are accommodated inthe chamber 71 at the latest. After accommodating the wafers W in thechamber 71, the wafers W are immediately rotated to start the dryingprocess.

It is noted that in practical, the respective "batch" processes at theloading/pick-up section 2 and the cleaning/drying section 3 and thecharging/unloading section 4 are simultaneously executed and therefore,the wafers W corresponding to two carriers C are respectivelyaccommodated in each of the processing parts 12 to 17 of thecleaning/drying section 3 and the rotary processing part 19. Note, apack of wafers W accommodated in each of the processing parts 12 to 17,19 will be referred as "a lot", hereinafter. Accordingly, theabove-mentioned balance adjustment for the autobalancers 75, 76 has tobe executed after the drying process for any lot of wafers W has beenfinished in the rotary processing part 19 and before the following lotof wafers W are loaded into the processing chamber 71 of the part 19.

Accordingly, in this embodiment, the balance adjustment is conducted inaccordance with a program shown in FIG. 13. Thus, at step S1, it isexecuted to unload a lot of wafers W to which the drying process hasbeen completed in the rotary processing part 19, by means of the waferchuck 38 of the conveying unit 32. At sequent step S2, the number ofwafers W, which are now accommodated in the processing part 17 and whichwill be accommodated in the processing chamber 71 of the rotaryprocessing part 19 next, is inputted into the controller 152 by thecentral control unit 150. In this regard, the inputting of the number ofwafers W into the controller 152 may be carried out at the deciding alot of wafers W which will be accommodated in the processing chamber 71next. Then, the controller 152 operates to decide respective positionsof the counterweights in the autobalancer 75, 76 on the basis of theobtained numbers of wafers W and thereafter, the controller 152 outputsa moving command for the counterweights to the autobalancers 75, 76.Consequently, the autobalancers in the autobalancers 75, 76 begin tomove, so that the above-mentioned balance adjustment is initiated asshown at step S3.

At step S4, by the central control unit 150, it is executed to calculatea difference X (X=A-B) between time A required for adjusting thebalance, i.e. time which is necessary for moving the counterweights inthe autobalancers 75, 76, and time B required for completing toaccommodate the next lot of wafers W in the processing chamber 71 of therotary processing part 19, i.e. time from taking out the wafers W fromthe processing part 17 by the wafer chuck 38 of the conveying unit 32till finishing to accommodate the wafers W in the processing chamber 71of the part 19.

At sequent step S5, it is judged whether the time A is equal to or lessthan the time B or not, i.e. the difference X is zero or a negativevalue. If the judgement at step S5 is Yes (i.e. X≦0), it means that whenthe process to accommodate the wafers W in the chamber 19 is completed,the adjustment for the balance of the autobalancers 75, 76 has beenalways finished. Therefore, in such a case, the routine goes to step S7where a process to transporting the wafers W from the processing part 17is executed as soon as the balance adjustment is started.

On the contrary, if the time A is longer than the time B (X>0), there isa possibility of situation that if the transporting of wafers W isstarted as soon as the operation of balance adjustment is started, theadjustment operation is not finished yet when the wafers W areaccommodated in the processing chamber 71 of the part 19. In such acase, many water marks may appear on the surfaces of the wafers Wdisadvantageously, since it is impossible to start to rotate the wafersW instantly.

Therefore, when the time A is longer than the time B (X>0), then theroutine goes to step S6. At step S6, it is executed to hold the startingof operation of the conveying unit 32 in readiness for the time X sincethe above balance adjusting operation has been started in theautobalancers 75, 76. In this way, after the time X has passed, thewafers W are taken out from the processing part 17 by the wafer chuck 38of the conveying unit 32 and accommodated in the processing chamber 71of the rotary processing part 19. With the above "stand-by" process, itis possible to realize the situation that the adjustment for the balanceof the autobalancers 75, 76 has been always finished when the process toaccommodate the wafers W in the chamber 19 is completed.

When the processes to restrict the wafers W between the lower and upperconstraint mechanisms 102, 103 in the processing chamber 71 of the part19 collectively and sequent accommodate the wafers W by closing thechamber 71 with the lid body 81 are completed in this way, then theroutine goes to step S8 where the motor 71 is immediately energized forrotation. Consequently, with the rotation of the wafers W, the watersticking on the surfaces is spattered around due to the centrifugalforce. Then, since the balance adjustment has been already finished, itis possible to reduce the vibrations caused by the rotation of wafers W.

Simultaneously, the gas-liquid removing mechanism 140 in the frame 70 isoperated to start. In detail, the inside pressure in the processingchamber 71 is reduced by an operation of the blower 142, so that freshair cleaned through a not-shown filter enters into the chamber 71. Sincethe fresh air is blown against the surfaces of the wafers W rotating inthe chamber 71, they are dried in consequence. The water removed fromthe surfaces is drained to the underside of the chamber 71 together withthe supply air from the blower 142 and thereafter, the only water istrapped by the drain 141.

With the completion of process for drying the wafers W, the routine goesto step S9 where the motor 74 is inactivated to stop the rotation ofwafers W. Next, the upper constraint mechanism 103 is turned upward byninety angles (90°) into so-called "turnout" condition, while the lidbody 81 is rotated to take a shelter, whereby the chamber 71 opensupward. Then, the wafer chuck 38 of the conveying unit 32, which hasbeen previously cleaned and dried in the processing part 18, descendsinto the chamber 71 to pick up the cleaned and dried wafers W therefrom.After picking up, the conveying unit 32 carries the wafers W to thecharging part 20 of the charging/unloading section 4. After completingthe above-mentioned processes in this way, the wafers W are charged intothe carrier C at the charging part 20 of the section 4 and sequentiallyunloaded to the outside of the cleaning system 1 at the unloading part21.

According to the shown embodiment of the present invention, which hasbeen described on the basis of the cleaning system 1 for cleaning thewafers W, since the objects to be processed are no sooner accommodatedinto the rotary processing part than the operation of the motor 74 isstarted, the water sticking on the surfaces of the wafers W scattersimmediately before the water is evaporated naturally due to thecentrifugal force applied on the objects. Accordingly, there is no fearof leaving water marks on the surfaces of the wafers W.

As mentioned above, according to the present invention, owing to theinstant starting to rotate the objects to be processed afteraccommodating them into the rotary processing part, it is possible toshorten time for processing. In addition, since a period from thecompletion to accommodate the objects till the starting to rotate themis remarkably short, it is possible to avoid the occurrence of troubleson the objects during the same period.

Finally, it will be understood by those skilled in the art that theforegoing description is one of the preferred embodiments of theprocessing apparatus and processing method, and that various changes andmodifications may be made to the present invention without departingfrom the spirit and scope thereof.

What is claimed is:
 1. A processing apparatus comprising:a rotaryprocessing part for rotating and drying plural sheets of objects to beprocessed collectively; a balance adjusting mechanism having at leastone counterweight for adjusting the balance of said rotary processingpart by moving said at least one counterweight in accordance with thenumber of said objects; counting means for counting the number of saidobjects accommodated in said rotary processing part; and control meansfor controlling the balance adjusting operation by said balanceadjusting mechanism in accordance with a predetermined relationshipbetween the number of said objects and respective positions of said atleast one counterweight, wherein said control means controls saidbalance adjusting mechanism in a manner so that the balance adjustingoperation of said balance adjusting mechanism is finished by the timesaid objects are accommodated in said rotary processing part, wherein aperiod provided from a beginning of the balance adjusting operation tothe end is represented by a letter A, while a period from a beginning oftransferring said object from a former processing part just before saidrotary processing part, to said rotary processing part to the end oftransferring, after which said objects are able to be rotary-processed,is represented by a letter B, and wherein said control means isconstructed so that, in case of A≦B, the transferring of said objectsinto said rotary processing part is started as soon as the balanceadjusting operation has been started, while in case of A>B, the objectswait for at least a time A B since the balance adjusting operation wasstarted, at the former processing part just before said rotaryprocessing part, then the transferring of said objects into said rotaryprocessing part is started.
 2. A processing apparatus comprising:one ormore processing parts for processing plural sheets of objects to beprocessed; a rotary processing part for collectively rotating and dryingsaid objects processed by said processing parts; a balance adjustingmechanism having at least one counterweight for adjusting the balance ofsaid rotary processing part by moving said at least one counterweight inaccordance with the number of said objects; counting means for countingthe number of said objects before said objects are processed by saidprocessing parts; and control means for controlling the balanceadjusting operation by said balance adjusting mechanism in accordancewith a predetermined relationship between the number of said objects andrespective positions of said at least one counterweight, wherein saidcontrol means controls said balance adjusting mechanism in a manner sothat the balance adjusting operation of said balance adjusting mechanismis finished by the time said objects are accommodated in said rotaryprocessing part, wherein a period provided from a beginning of thebalance adjusting operation to the end is represented by a letter A,while a period from a beginning of transferring said object from aformer processing part just before said rotary processing part, to saidrotary processing part to the end of transferring, after which saidobjects are able to be rotary-processed, is represented by a letter B,and wherein said control means is constructed so that, in case of A≦B,the transferring of said objects into said rotary processing part isstarted as soon as the balance adjusting operation has been started,while in case of A>B, the objects wait for at least a time AB since thebalance adjusting operation was started, at the former processing partjust before said rotary processing part, then the transferring of saidobjects into said rotary processing part is started.
 3. A processingapparatus comprising:a rotary processing part for rotating and dryingplural sheets of objects to be processed collectively; a balanceadjusting mechanism having at least one counterweight for adjusting thebalance of said rotary processing part by moving said at least onecounterweight in accordance with the number of said objects; countingmeans for counting the number of said objects accommodated in saidrotary processing part; and control means for controlling the balanceadjusting operation by said balance adjusting mechanism in accordancewith a predetermined relationship between the number of said objects andrespective positions of said at least one counterweight, wherein saidcontrol means controls said balance adjusting mechanism in a manner sothat the balance adjusting operation of said balance adjusting mechanismis finished by the time said objects are accommodated in said rotaryprocessing part, and wherein said predetermined relationship between thenumber of said objects and the position of said at least onecounterweight is introduced from a predetermined relationship betweenthe number of said objects and resultant force of said at least onecounterweight, and wherein, providing that the number of said objects isrepresented by a variable x while the resultant force is represented bya variable y, and certain constant values are represented by constants aand b, said predetermined relationship between the number of saidobjects and the resultant force is expressed by an equation as below:

    y=ax+b.


4. A processing apparatus comprising:one or more processing parts forprocessing plural sheets of objects to be processed; a rotary processingpart for collectively rotating and drying said objects processed by saidprocessing parts; a balance adjusting mechanism having at least onecounterweight for adjusting the balance of said rotary processing partby moving said at least one counterweight in accordance with the numberof said objects; counting means for counting the number of said objectsbefore said objects are processed by said processing parts; and controlmeans for controlling the balance adjusting operation by said balanceadjusting mechanism in accordance with a predetermined relationshipbetween the number of said objects and respective positions of said atleast one counterweight, wherein said control means controls saidbalance adjusting mechanism in a manner so that the balance adjustingoperation of said balance adjusting mechanism is finished by the timesaid objects are accommodated in said rotary processing part, andwherein said predetermined relationship between the number of saidobjects and the position of said at least one counterweight isintroduced from a predetermined relationship between the number of saidobjects and resultant force of said at least one counterweight, andwherein, providing that the number of said objects is represented by avariable x while the resultant force is represented by a variable y, andcertain constant values are represented by constants a and b, saidpredetermined relationship between the number of said objects and theresultant force is expressed by an equation as below:

    y=ax+b.


5. A processing apparatus comprising:one or more processing parts forprocessing plural sheets of objects to be processed; a rotary processingpart for collectively rotating and drying said objects processed by saidprocessing parts; counting means located outside of said rotaryprocessing part for counting the number of said objects before saidobjects are processed by said processing parts; a balance adjustingmechanism having at least one counterweight for adjusting the balance ofsaid rotary processing part, by moving said at least one counterweightin accordance with the number of said objects; and control means formemorizing the number of said objects counted by said counting means andcontrolling the balance adjusting operation by moving said balanceadjusting mechanism in accordance with a predetermined relationshipbetween the number of said objects and respective positions of said atleast one counterweight.
 6. A processing apparatus comprising:a rotaryprocessing part for rotating and drying plural sheets of objects to beprocessed collectively; counting means located outside of said rotaryprocessing part for counting the number of said objects; a balanceadjusting mechanism having at least one counterweight for adjusting thebalance of said rotary processing part by moving said counterweights inaccordance with the number of said objects counted by said countingmeans; and control means for controlling the balance adjusting operationby said balance adjusting mechanism in accordance with a predeterminedrelationship between the number of said objects and respective positionsof said at least one counterweight, wherein said control means controlssaid balance adjusting mechanism in a manner that the balance adjustingoperation of said balance adjusting mechanism has been finished by thetime said objects are accommodated in said rotary processing part.
 7. Aprocessing apparatus comprising:one or more processing parts forprocessing plural sheets of objects to be processed; a rotary processingpart for collectively rotating and drying said objects processed by saidprocessing parts; counting means located in the outside of said rotaryprocessing part for counting the number of said objects before saidobjects are processed by said processing parts; a balance adjustingmechanism having at least one counterweight for adjusting the balance ofsaid rotary processing part, by moving said at least one counterweightin accordance with the number of said objects; and control means formemorizing the number of said objects counted by said counting means andcontrolling the balance adjusting operation by moving said balanceadjusting mechanism in accordance with a predetermined relationshipbetween the number of said objects and respective positions of said atleast one counterweight, wherein said control means controls saidbalance adjusting mechanism in a manner that the balance adjustingoperation of said balance adjusting mechanism has been finished by thetime said objects are accommodated in said rotary processing part.